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ATEX vs. IECEx: Zones, Certification, and Geographic Applicability

At first glance, ATEX and IECEx appear very similar, but they have some important differences you should know about. Understanding these differences is key to complying with (inter)national regulations and keeping your employees safe.

Both ATEX and IECEx are used for equipment in hazardous areas, also known as explosive atmospheres. ATEX comes from European laws, while IECEx is an international standard recognized globally and set by the International Electrotechnical Commission (IEC). Both standards employ an almost identical zoning system that categorizes hazardous areas based on the presence of gas or dust, and the level of risk.

Even though ATEX and IECEx seem similar, this article is here to help clear up any confusion and highlight the unique aspects of each certification. This way, you can make sure you’re on the right track when it comes to compliance and safety.

Comparison Table

To promptly address your questions and for your reference, we have compiled the table below:

OriginEuropean Union CommissionIndustry Representatives
Geographic AcceptanceMandatory in European Economic Area, recognized in most countries.Global recognition, voluntary adoption. Law in 5 countries.
Directive/SchemeATEX Directives (ATEX 153 & ATEX 114)IECEx Certified Equipment Scheme
Services Scheme
Conformity Mark Licensing System
Competent Persons Scheme
Equipment Categories1, 2, 3 for mining and non-mining applicationsProtection levels ‘a’, ‘b’, ‘c’
MarkingsCE marking, ‘Ex’ symbol, equipment group and category, gas/dust specification and NoBo (ExNB) numberCoC equipment number, ExCB number, protection level
Standards ComplianceBoth standards are technically identical since 2005.
Flexible, standards as a “deemed to comply” method, more room for interpretationStrict adherence to standards
Certification ProcedureHandled by Notified Bodies (ExNB)Involves Test Report (ExTR), handled by ExCB (Ex Certification Body)
Certification DocumentEU Type Examination CertificateCertificate of Conformity
Quality AuditQuality Assurance Notifications (QAN)Quality Assessment Report (QAR)

What is ATEX?

ATEX is the name commonly given to the two European Union directives for controlling explosive atmospheres:

ATEX 153 (formerly ATEX 137) Directive 99/92/EC (also known as ‘ATEX Worker Protection Directive’): This directive focuses on the safety and health protection of workers potentially at risk from explosive atmospheres. It outlines the minimum requirements for improving the safety and health protection of workers at risk from explosive atmospheres. The directive requires employers to classify areas where hazardous explosive atmospheres may occur into zones. The zone classification depends on the nature (gas or dust), likelihood and duration of the occurrence of an explosive atmosphere.


ATEX 114 (formerly ATEX 95) Directive 2014/34/EU (formerly 94/9/EC and also known as ‘ATEX Equipment Directive’): This directive applies to equipment (electrical and non-electrical) and protective systems intended for use in potentially explosive atmospheres. It defines the essential health and safety requirements and conformity assessment procedures, to be applied before such equipment is placed on the EU market.

The term “ATEX” itself comes from the French “ATmosphères EXplosibles”. It is a regulatory framework meant to ensure the safety of products used in places where there is a risk of explosion due to the presence of flammable gases or dusts. Manufacturers must ensure that their products meet strict ATEX guidelines if they are to be used within the EEA (European Economic Area). Products that meet these stringent safety standards are marked with the distinctive ‘Ex’ symbol to identify their certification status.

ATEX is European legislation and, as such, is compulsory across all EEA countries, where the ATEX directives have been adopted into national law. For instance, in the UK, these directives are encompassed within the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR).

What is IECEx?

IECEx, short for ‘The International Electrotechnical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres’, is a global standard focused on ensuring the safety of equipment used in potentially explosive environments. Unlike ATEX, which is mandatory in the EEA under European Union law, IECEx is an international framework recognized worldwide, and part of IEC.   

According to the IECEx Management Committee, their voluntary certification system aims to facilitate international trade by providing a consistent set of standards for explosive atmosphere protection. In practice a lot of countries and governing bodies recognize and participate in IECEx, including the UN, most of Europe, China and the USA. This is why IECEx certification is often referred to as ‘global certification’ when it comes to hazardous area equipment, companies, and services (e.g. repairs).

Whereas ATEX originates form two European Directives, IECEx consists of four schemes, namely:

  • IECEx Certified Equipment Scheme
  • IECEx Certified Services Scheme
  • IECEx Conformity Mark Licensing System
  • IECEx Certified Competent Persons Scheme

The design standards, production requirements, and testing methods of both hazardous location certification systems are very similar. Since 2005, the technical standards have become technically identical with only a few exceptions. The EU Directive is updated according to changes in the IECEx schemes. ATEX certification can even be based on an IECEx Test report. Both use the same zone classification system, with Ex zones 0,1,2, and 20,21,22.

Comparison: ATEX vs. IECEx

Now that we have covered the basics of both IECEx and ATEX, let’s take a deep dive into the similarities and differences of both certifications.

Ex Zones and Equipment Categories

Both IECEx and ATEX employ an identical zone-classification system that assesses the level of danger in an environment, guiding the selection of appropriate equipment for use in such areas, as illustrated in the table below.

Danger level in hazardous areaIECEx and ATEX ZoneATEX CategoryIECEx Protection Level
Continuous presence of explosive atmosphere0, 201‘a’
Occasional presence of explosive atmosphere1, 212‘b’
Abnormal presence of explosive atmosphere2, 223‘c’

ATEX: Equipment Groups and Categories

Under ATEX regulations, equipment is systematically classified into two main groups—those intended for mining and non-mining applications—and further into categories 1, 2, and 3, reflecting the level of safety required. These groups and categories are shown in the table below:

Equipment GroupEquipment CategoryDescription
I (Mining)M1Equipment must remain functional in an explosive atmosphere
I (Mining)M2Equipment must be de-energized in the explosive atmosphere
II (Non-mining)1High level of protection
II (Non-mining)2Medium level of protection
II (Non-mining)3Normal level of protection
Discover key aspects of ATEX zones and equipment categories for safe operation in hazardous areas in our informative article.

IECEx: Protection Levels Instead of Equipment Categories

The IECEx system uses protection levels ‘a’, ‘b’, and ‘c’ for safe equipment design, which ATEX also uses for intrinsic safety. That’s why it can be tricky to tell the difference between the two certifications just by looking at their markings.

Summarizing, under both certifications, the Ex zones are classified in the same manner. The equipment protection level is however designated differently, as shown in the tables above.

Global Certification Guide: Matching Certificates with Countries

ATEX is a set of safety laws from the European Union that all member countries must follow. Even after leaving the EU in 2023, the UK still upholds ATEX laws under its own regulations known as DSEAR.

Additionally, countries outside the EU like have chosen to apply ATEX regulations too.

  • Norway
  • Iceland
  • Switzerland
  • Turkey
  • Liechtenstein

In these countries, the law dictate that any equipment used in hazardous areas must be ATEX certified.

IECEX – Global Certification?

IECEx certification is not mandatory—it’s a choice. ATEX and IECEx share the same technical standards; ATEX is based on IECEx standards. If you get an IECEx certificate, you can use it to apply for ATEX certification. That’s why you’ll often see equipment with both certifications. But the reverse isn’t true; ATEX doesn’t support the certification process for IECEx certification.

Most countries outside the EU are fine with any proof that equipment is safe in explosive areas.

However, five countries have officially recognized IECEx as an acceptable option within their safety laws, sometimes with a few special conditions:

  • Australia
  • New Zealand
  • Singapore
  • India
  • Israel

Some countries, like Brazil, have their own safety standards such as INMetro. But even there, you can base your INMetro certification on an IECEx certificate.

United States: Classes and Divisions

The United States and Canada have traditionally used their classes and divisions system to classify hazardous areas. Even though the US has joined the IECEx system, it’s still forbidden to use IECEx equipment in an area that’s designated by classes and divisions instead of zones. A good thing to remember is that divisions and zones don’t mix.

ATEX ZoneNorth American ClassNorth American Division
0 or 20I or II1
1 or 21
2 or 22I or II2

Global Acceptance

Many countries aren’t specific about whether ATEX or IECEx certification is required. They generally ask for certified equipment without stating a preference for one standard over the other. This means that in such countries, both ATEX and IECEx certifications are usually acceptable. This is common in places like the Middle East and Africa, where the focus is on ensuring equipment meets international safety standards for hazardous areas.

A map of the world showing the countries where ATEX is the leading standard.

Product Markings

ATEX markings are designed to provide necessary information for the correct choice and safe use of equipment in explosive atmospheres. However, markings can be confusing due to a lack of standardization and misalignment with the directive’s classification scheme. The specifics of each equipment marking are detailed in user instructions.

Key Elements of ATEX Markings

  • CE-marking with the Notified Body's identification number, if involved.
  • Explosion protection marking: "εx" inside a hexagon.
  • Equipment Group according to ATEX directive (I or II) or EN 60079-0 (I, II, III).
  • Equipment Category (1, 2, 3).
  • For Group II (ATEX) or Groups II and III (EN 60079-0): G, D, or DG for explosive atmosphere suitability.
  • "Ex" marking for explosion protection and specific Ex code for type of protection (e.g., “tD A21”).
  • Gas or Dust group specification (e.g., IIC).
  • Maximum surface temperature by class or °C (e.g., T4, “T80 °C”).
  • Equipment Protection Level (EPL) (e.g., “Gb”).

If all possible elements are used, some duplication of information may occur. ATEX marking also covers multi-category equipment, Article 1.2 devices (required for safe functioning outside ATEX zones), components (essential for safe functioning but without autonomous function), and assemblies (combination of ATEX equipment).

IECEx Marking Differences

IECEx markings closely resemble their ATEX counterparts but with notable differences. Unlike the other standards, IECEx does not feature the ‘Ex’ equipment logo, the CE marking, or designate equipment groups and categories. Furthermore, the process does not involve a Notified Body (ExNB); instead, it relies on an Ex Certification Body (ExCB), which is why the marking includes an ExCB number.

Certificate NumberEU Type Examination   Certificate NumberCoC Equipment Number
CE MarkingRequired (EU law)Not required, IEC Marking instead
CertificationNoBo (ExNB) NumberExCB Number
Ex equipment logoRequiredNot included
Equipment GroupRequiredEPL Ma or Mb
Equipment Category1, 2 or 3‘a’, ‘b’ or ‘c’
EnvironmentGas or Dust (G or D)Not included

IECEx vs ATEX Standards

IECEx strictly adheres to ISO/IEC 17065 principles, where full conformity with IEC International Standards is compulsory for certification. It’s a rule-based system where meeting these international standards is a necessity. There is no room for interpretation.

ATEX, on the other hand, is more flexible. While it mandates compliance with the Essential Health and Safety Requirements (EHSRs) outlined in Annex II, it considers conformity with standards as a pathway or a “deemed to comply” method. This implies that while ATEX encourages adherence to standards, it doesn’t make it an absolute requirement. Manufacturers often use these standards to evaluate their products and to demonstrate their alignment with the EHSRs.

Under ATEX, any recognized standard or local health and safety regulation that matches the EHSRs can be applied. The European Commission provides a list of Harmonised Standards to assist in this. These CEN/CENELEC standards are specially crafted to offer a presumption of conformity with the EHSRs, suggesting that compliance with these standards is a strong indicator of meeting ATEX requirements, although not guaranteed.

It’s also worth noting that Ex CENELEC standards are typically technically identical to the corresponding IEC standards, which shows a significant overlap between the two systems.

However, the key distinction lies in the obligatory nature of standards adherence in IECEx, as opposed to the more interpretative approach of ATEX which allows for alternative compliance demonstrations aligned with the EHSRs.

Which Standards Are Better?

In practice, IECEx is stricter with standards, which might seem to offer safer products. ATEX, while also ensuring the same level of safety, provides more flexibility, which can be beneficial for complex engineering challenges. Both systems ensure safety, but the choice may depend on the specific needs of the project.

Certification Procedure

For IECEx certification, the IECEx Certified Equipment Scheme involves three key documents issued by IECEx Certification Bodies (ExCBs): the IECEx Test Report (ExTR), the IECEx Quality Assessment Report (QAR), and the IECEx Certificate of Conformity (CoC) for equipment.

Similarly, for the Certified Service Facility Scheme and the Certified Competent Person Scheme, IECEx CoCs are issued along with Facilities Assessment Report Forms (FAR) and Personnel Competence Assessment Reports (PCAR), respectively. These certifications are part of a systematic and standardized process detailed in the IECEx Rules of Procedure and Operational Documents, with all technical decisions and certifications publicly accessible on the IECEx online system. We hope you’re still with us after all those names and abbreviations..

ATEX Certification Procedure

ATEX certification, handled by Notified Bodies (ExNB), includes EU Type Examination Certificates which document the evaluation and testing against EN 60079 Standards, and Ex Quality Assessment Notifications (QAN) that assess the manufacturer’s quality assurance system in line with ISO/IEC 80079-34. Unlike IECEx’s online repository, ATEX documents are traditionally available in hard copy format.


Both IECEx and ATEX share similarities in their assessment processes for quality assurance, but IECEx provides a more integrated and publicly transparent system with its online certification database, while ATEX follows a more traditional documentation process with paper-based certificates and notifications.

It’s crucial to emphasize that ATEX regulations do not necessitate the involvement of a notified body for Category 3 equipment (zones 2 and 22). Manufacturers have the option to self-certify this equipment.

Conformity and Governance

Governance within the IECEx system is designed to unify international certification processes, making sure that all Certification Bodies (ExCBs) and Test Laboratories (ExTLs) maintain a high level of expertise and operate under a single, consistent set of procedures for testing and certification across all hazard zones. This system does not differentiate between zones 0, 1, or 2, aiming for a global standardization of Ex equipment certification.

For ATEX, the approach to governance is more varied, with multiple conformity assessment paths available. The ATEX system allows manufacturers to internally control production and declare equipment safety, emphasizing the manufacturer’s responsibility for ensuring compliance with EU directives and the safety of the equipment in its intended operational context. Not all paths under ATEX require third-party intervention, and the system relies on the manufacturer’s own declaration of conformity for Category 3 equipment, which can be supported by an IECEx certificate.

Differences between IECEx Certification Bodies (ExCB’s) and ATEX Notified Bodies (ExNBGs)

IECEx Certification Bodies (ExCBs) and Testing Laboratories (ExTLs) are chosen through a rigorous qualification process which includes an initial peer assessment by an IECEx Assessment Team, ongoing surveillance audits, and re-assessment audits every five years. This process ensures that ExCBs and ExTLs have the necessary technical expertise, equipment, and facilities to conduct proper testing and certification. The assessment and administrative activities are managed by the IECEx Technical Secretariat under the direction of various IECEx committees and supported by specialist working groups.

ATEX Notified Bodies (ExNBGs), on the other hand, are appointed by the national governments of EU member states. Unlike IECEx, there is no common international assessment system for ExNBGs; their surveillance and assessment are subject to the requirements of their respective national governments. ATEX is supervised by an ATEX Working Group and an EU Commission Standing Committee Working Group.

Different Certificates and Conformity Documents

An IECEx Certificate of Conformity (CoC) for equipment is an internationally recognized document issued by an IECEx Certification Body after a product has successfully passed testing and assessment against IEC standards.

On the other hand, an EU Type Examination Certificate, under ATEX, is a document that signifies a product has been evaluated and tested against the relevant EN 60079 standards for the European market. It is part of the ATEX certification process and is issued by an ATEX Notified Body.

ATEX also includes the use of a Declaration of Conformity (DoC) for compliance. A prime example of this is our explosion proof air conditioner designed for ATEX-regulated environments. For more details, visit our product page: ATEX Certified Air Conditioner.

Both documents are used as an ‘Ex certificate’ for hazardous area equipment.

The Takeaway

IECEx and ATEX share technically very similar, but their certification processes differ. While both enjoy global recognition, ATEX is obligatory under European law. Unlike ATEX, IECEx omits equipment groups and features distinct categories (‘a’, ‘b’ and ‘c’). Notably, self-certification is allowed for Zone 2 and 22 equipment under ATEX, but this isn’t applicable for IECEx, where a Certificate of Conformity (CoC) must be issued by an ExCB.

If you have any inquiries regarding the distinctions and resemblances between the two, feel free to reach out to us!